Crumble the sausage (if using) into a skillet over medium-high heat. Cook and stir until no longer pink. Remove from the heat and set aside.

Fill a large pot halfway with water(about 2 quarts), and bring to a boil. Add the sausage, and cover the pot. Return to a boil. Add the beets, and cook until they have lost their color. Add the carrots and potatoes, and cook until tender, about 15 minutes. Add the cabbage, and the can of diced tomatoes.

Heat the oil in a skillet over medium heat. Add the onion, and cook until tender. Stir in the tomato paste and water until well blended. Transfer to the pot. Add the raw garlic to the soup, cover and turn off the heat. Let stand for 5 minutes. Taste, and season with salt, pepper and sugar.

Ladle into serving bowls, and garnish with sour cream, if desired, and fresh parsley.